Cruciform Vent in Battery End Wall for Pressure Relief
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Solution Overview
Problem
Conventional alkaline electrochemical cells face issues with excessive gas pressure buildup due to the limited space for electrochemically active materials, as existing pressure relief vents either consume valuable volume or are susceptible to damage during manufacturing.
Innovation Solution
A pressure relief vent mechanism with a reduced thickness groove, formed as a cruciform shape with at least five radial segments, is integrated into the closed end wall of the cell container, allowing for effective gas release while minimizing the risk of damage and maintaining a low profile seal assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional vent is formed in the annular polymeric seal, then pressure relief is achieved, but the assembly consumes significant volume within the battery can
Solution Approach 1:
The vent mechanism is extracted from the seal assembly and relocated to the bottom end wall of the can. This separates the venting function from the sealing function, allowing the seal assembly to be minimized while the vent is formed directly in the can structure where it does not consume additional volume.
2Reliability
If a thin vent groove is formed in the bottom end wall, then pressure relief is achieved, but the vent is susceptible to damage during manufacturing
Solution Approach 1:
The vent groove is designed with an asymmetric cruciform pattern featuring radial segments of varying thickness. The segments extend radially from a central location with different thickness profiles, allowing the vent to rupture at controlled pressure while maintaining sufficient thickness in critical areas to resist damage during impact molding and manufacturing processes.
Solution Approach 2:
The vent is divided into multiple radial segments extending from the center, creating a cruciform pattern. This segmentation allows the vent to rupture in a controlled manner along the groove lines while the overall structure maintains sufficient strength to withstand manufacturing operations.
3Stability of the object's composition
If the peripheral flange of the cover is welded symmetrically, then structural stability is achieved, but gas venting is inhibited due to sealing against the bottom end wall
Solution Approach 1:
The welds are positioned asymmetrically around the peripheral flange rather than at symmetric intervals. This asymmetric positioning prevents the flange from forming a complete seal against the bottom end wall, creating gaps that allow vented gases to escape while maintaining sufficient structural stability through the distributed weld connections.
Data Source
AI summary
An electrochemical cell is provided with an enhanced pressure relief vent formed in a closed end of the cell container that achieves effective venting of gas from the closed end of the container. The electrochemical cell including a container having a first end, a second end, a side wall extending between the first and second ends, and an end wall extending across the first end. The cell has a positive electrode, a negative, and an aqueous alkaline electrolyte, all disposed in the container. The cell further includes a pressure relief vent having a reduced thickness groove formed in the end wall of the container. The reduced thickness groove is formed having eight segments extending radially from a central location. A cover is welded on the end wall of the container via at least three welds, wherein the angular spacing between two adjacent welds is greater than 120°.